I think when the book was written, digital computers were the latest tech
and analog computers had been actually pretty common for 30 years.
Technology included fluid (
) and
electronic.
I don't think the title was related to the analytical engine, my take would
be that it was just an encouragement to the reader that it was an
achievable and usable device.
It may be that the military uses contributed to the lack of public
documentation of the mechanical systems.
On Sun, Jul 21, 2024 at 9:03 AM Dave Wade G4UGM via cctalk <
cctalk(a)classiccmp.org> wrote:
  -----Original Message-----
 From: Tony Duell via cctalk <cctalk(a)classiccmp.org>
 Sent: Sunday, July 21, 2024 5:42 AM
 To: General Discussion: On-Topic and Off-Topic Posts <
 
 cctalk(a)classiccmp.org>
  Cc: Steve Lewis <lewissa78(a)gmail.com>om>; Tony
Duell
 <ard.p850ug1(a)gmail.com>
 Subject: [cctalk] Re: the 1968 how to build a working digital computer
 On Sun, Jul 21, 2024 at 3:08 AM Steve Lewis via cctalk <
 
 cctalk(a)classiccmp.org>
  wrote:
 > What I meant was that in the title of the book they use "digital
 
 computer"
   and I
wonder if there was ever a book describing a mechanical "analog
 computer" - and what they might even look like.
 
 There have been mechanical analogue computers and I have at least one
 
  book
  describing them on my shelves.
 Typically they used disc integrators with an igenious arrangement of
 
 strings and
  drums as a torque amplifier. These were then
coupled by gearing which
 
 had to
  be set up for each problem (simple gear trains
correspond to fixed gain
 amplifiers, differential gear trains to differential amplfiiers, etc).
 I doubt you could make one from cardboard, but there was at least one UK
 University that made a simple one from Meccano (similar to Erector Sets
 
 across
  the Pond?). It was on show, not operating, in the
London Science Museum
 
 at
  one time, but I think it's in storage now,
 
 Several people have made Analog Computers from Meccano. The "first" I
 think was at Manchester University in the UK intended as a prototype or
 proof of concept it was later replaced by an engineered device.
 Both were on display in the Science Museum but I believe they are now in
 Storage. Cambridge University UK also had a Meccano Analog Computer. I
 believe this is the one now on display at MOTAT, Aukland, New Zealand
 
https://motat.nz/
 there are some pictures of it on my one drive (if it asks you to sign in
 and you don't wish to use an incognito window)
 
https://1drv.ms/f/s!Ag4BJfE5B3onlsxny71p3CPOQV4svA?e=aSdamK
 in more recent times Tim Robinson built one...
 
https://www.meccano.us/differential_analyzers/robinson_da/index.html
 .. so there are some clues on how to do it about, but no book as far as I
 know
 -tony
 
 Dave
 G4UGM